Damper and washing machine having the same

ABSTRACT

A damper includes: a cylinder having a receiving space with a predetermined depth in a longitudinal direction on one side thereof; a rod inserted to be movable relatively in a longitudinal direction in the receiving space of the cylinder; a friction surface formed at one side of the cylinder and the rod; a friction member positioned at the cylinder or the rod and rubbing on the friction surface; a thermally deformable member being deformed according to a change in a temperature to make the friction member be tightly attached to the friction surface or separated therefrom; and a heating unit for thermally deforming the thermally deformable member. The damper absorbs the small and large amount of vibrations to thereby prevent transfer of vibration to other parts.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a damper and a washing machine having the damper, and more particularly, to a damper capable of minimizing transfer of vibration to other part by generating a damping force for absorbing various levels (or forms/sizes) of vibrations as transferred, and a washing machine having the damper.

[0003] 2. Description of the Background Art

[0004] In general, a washing machine washes the laundry by performing a washing operation, a rinsing operation, and a dewatering operation. There are many kinds of washing machines depending on washing methods as follows: For example, a first one is to wash the laundry by giving the laundry an impact of a whirl flow generated when a washing bar with blades is rotated at the center of a washing tub; a second one is to wash the laundry by giving the laundry an impact of a whirl flow generated when rotation blades mounted at a bottom of the washing tub are rotated; and a third one is to wash the laundry by a laundry-falling impact when a drum is rotated with the laundry therein in a horizontal direction.

[0005]FIG. 1 shows an example of a washing machine.

[0006] As shown in FIG. 1, a washing machine includes a cabinet 100 having a predetermined shape of internal space; a tub 210 positioned inside the cabinet 100, a drum 220 rotatably inserted in the tub 210 and receiving the laundry; a driving motor 230 mounted at a rear side of the tub 210 and rotating the drum 220; a spring 110 mounted between the cabinet 100 and the upper portion of the tub 210 and elastically supporting the tub 210; a damper 300 mounted between the cabinet 100 and a lower portion of the tub 210 and absorbing vibration; a water supply unit (not shown) for supplying washing water into the tub 210; a water discharge unit (not shown) for discharging washing water from the tub 210; and a door (not shown) for opening and closing the drum 220.

[0007] The tub 210, the drum 220 and the driving motor 230 constitute a tub assembly 200, which is supported by the damper 300 and the spring 110.

[0008] With such a washing machine, a washing process is performed such that the door is opened, the laundry is put into the drum 220, the door is closed, a detergent and washing water are input, and then, the drum 220 is rotated as the driving motor 230 is driven.

[0009] After the washing process is completed, a rinsing process proceeds, and washing water is discharged by the water discharge unit, and subsequently, a dewatering process is performed to remove washing water remaining in the laundry by a centrifugal force generated by rotating the drum 220 at a high speed. In this manner the laundry is washed.

[0010] In general, when the laundry is washed or dewatered, vibration is generated from the tub assembly. But such vibration is absorbed by the spring 110 and the damper 300, so as to be restrained in its transfer to the cabinet 100.

[0011] If the vibration generated from the tub assembly 200 is transferred to the cabinet 100 as it is without being absorbed, a severe vibration noise would be generated from the cabinet 100 due to the received vibration. This would cause an uneasiness to users as well as degrading a reliability of a product. Thus, minimizing of the vibration noise is most critical subject for the washing machine.

[0012]FIG. 2 is a partial sectional front view of a damper applied to the washing machine.

[0013] As shown in FIG. 2, the damper 300 includes a first body 310 having one side coupled to the tub 210 in a manner of being relatively moved and a cylindrical friction surface 311 at the inner side of the other side; a second body 320 having one side coupled to the cabinet 100 so as to be relatively movable and the other side inserted in the friction surface 311 of the first body 310; and a friction member 330 being in contact with the side of the friction surface 311 of the first body, fixedly coupled to the second body 320, and generating a frictional force in its movement. A guide bush 340 is coupled at an entrance of the friction surface 311 of the first body in order to cover a gap with the second body 320.

[0014] The friction member 330 is formed in a ring type with a predetermined thickness and length. A coupling groove 321 is formed at an outer circumferential surface of the second body 320 and has a predetermined length and depth. When the friction member 330 is inserted into the coupling groove 321 of the second body, the outer circumferential surface of the friction member 330 is in contact with the inner circumferential surface of the first body 310, that is, with the friction surface 311.

[0015] When the vibration generated from the tub assembly 200 is transferred to the damper 300, the first body 310 is moved in a linear direction due to the vibration, the friction member 330 is relatively moved, causing a friction between the outer circumferential surface of the friction member 330, and the vibration transferred from the tub assembly 200 is absorbed by the friction.

[0016] However, the washing machine has the following problems.

[0017] That is, since vibration levels generated from the tub assembly 200 differ during the entire process of the laundry washing, the various levels of vibration generated from the tub assembly 200 can not be sufficiently absorbed by the damper 300 generating a predetermined friction, and thus, much vibration noise is inevitably generated.

[0018] In detail, in the washing process, a normal level of vibration is generated during the washing process, and then, in the dewatering process, an excessive vibration is generated until a speed reaches a normal dewatering speed, and at the normal dewatering sped, a normal level of vibration is generated.

[0019] Generally, the conventional damper 300 generates a predetermined friction damping force. Thus, if the friction damping force is adjusted to the normal level of vibration, when an excessive vibration is generated, a vibration transfer rate is relatively increased to generate a vibration noise.

[0020] Meanwhile, if the friction damping force is adjusted to the excessive vibration, when a small level of vibration is generated, the vibration is transferred to the cabinet 100 as it is, generating a vibration noise.

SUMMARY OF THE INVENTION

[0021] Therefore, an object of the present invention is to provide a damper generating a damping force for absorbing various levels of vibrations according to vibrations transferred in various levels to minimize transfer of the vibrations to other parts, and a washing machine having the damper.

[0022] To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, there is provided a damper including: a cylinder having a receiving space with a predetermined depth in a longitudinal direction on one side thereof; a rod inserted to be movable relatively in a longitudinal direction in the receiving space of the cylinder; a friction surface formed at one side of the cylinder and the rod; a friction member positioned at the cylinder or the rod and being in a rubbing contact with the friction surface; a thermally deformable member being deformed according to a change in a temperature to make the friction member be tightly attached to the friction surface or separated therefrom; and a heating unit for thermally deforming the thermally deformable member.

[0023] To achieve the above objects, there is also provided a washing machine including a cabinet having an internal space in a predetermined shape and a tub positioned inside the cabinet and filled with washing water, including: a cylinder having a receiving space with a predetermined depth in a longitudinal direction at one side and being coupled to the cabinet or to the tub at the other side; a rod having one side inserted to be movable relatively in a longitudinal direction in the receiving space of the cylinder and the other side coupled to the cabinet or the tub; a friction surface formed at the cylinder or at the rod; a friction member positioned at the cylinder or at the rod and being in a rubbing contact with the friction surface; a thermally deformed member for making the friction member be tightly attached to the friction surface or separated therefrom by being deformed according to a temperature change; and a heating unit for thermally deforming the thermally deformable member.

[0024] The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention.

[0026] In the drawings:

[0027]FIG. 1 is a front sectional view showing an example of a general washing machine;

[0028]FIG. 2 is a front sectional view showing a damper of the washing machine;

[0029]FIG. 3 is a front sectional view showing an example of a damper in accordance with the present invention;

[0030]FIG. 4 is a partially enlarged sectional view of the damper;

[0031]FIG. 5 is a side sectional view of the damper;

[0032]FIGS. 6 and 7 are front sectional view and partially enlarged view of a damper having a thermally deformable member in accordance with the present invention;

[0033]FIG. 8 is a side sectional view of the damper;

[0034]FIG. 9 is a front sectional view showing a washing machine having the damper in accordance with the present invention; and

[0035]FIGS. 10 and 11 are sectional view showing operational states of the damper in accordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0036] Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings.

[0037]FIG. 3 is a front sectional view showing a damper in accordance with the present invention, FIG. 4 is a partial enlarged sectional view of the damper, and FIG. 5 is a side sectional view of the damper.

[0038] As shown in these drawings, the damper includes a cylinder 410 having a receiving space 411 with a predetermined depth in a longitudinal direction at one side; a rod 420 inserted to be movable relatively in a longitudinal direction into the receiving space 411 of the cylinder 410; a friction surface (FS) formed at the cylinder 410 or at the rod 420; a friction member 430 positioned at the cylinder 410 or at the rod 420 and rubbing on the friction surface (FS); a thermally deformable member 440 for making the friction member 430 be tightly attached to the friction surface (FS) or separated therefrom by being deformed according to a temperature change; and a heating unit 450 for thermally deforming the thermally deformable member 440.

[0039] The cylinder 410 includes the cylindrical receiving space 411 formed in the longitudinal direction at one side of a body part 412 having a predetermined length and outer diameter, and a coupling unit 413 is formed at the other side of the body part 412. And the friction surface (FS) is formed at the inner circumferential surface of the receiving space 411.

[0040] As to the rod 420, a coupling unit 422 is formed at one side of a cylindrical body 421 having a predetermined length and outer diameter, and a coupling groove 423 is formed at the other side thereof. The coupling groove 423 of the rod 420 is formed in a ring type with a predetermined length and depth at an outer circumferential surface of the cylindrical body 421.

[0041] The outer diameter of the cylindrical body 421 is smaller than an inner diameter of the receiving space 411, and the coupling groove 423 is positioned inside the receiving space 411 of the cylinder.

[0042] The friction member 430 is made of a material having an elasticity such as a grease-absorbed sponge or rubber. The friction member 430 is formed in a ring type with a predetermined thickness and length, or one side thereof can be cut out with a predetermined width.

[0043] As for the thermally deformable member 440, when it is heated at a high temperature, it contracts, whereas if its temperature is dropped, the thermally deformable member 440 expands.

[0044] The thermally deformable member 440 is a shape memory alloy. The shape memory alloy is formed in a ring type with a predetermined thickness and length, one side of which is cut out with a predetermined width.

[0045] The thermally deformable member 440, that is, the shape memory alloy, is inserted and coupled to the coupling groove 423 of the rod. The thermally deformable member 440 and the rod 420 can be coupled in various forms.

[0046] The friction member 430 is coupled at an outer circumferential surface of the thermally deformable member 440. A coupling groove 441 is formed with a predetermined length and depth at the outer circumferential surface of the thermally deformable member 440, and the friction member 4320 is inserted and coupled into the coupling groove 441 of the thermally deformable member. At this time, the outer circumferential surface of the friction member 430 is tightly attached to the friction surface (FS) of the receiving space 411 of the cylinder. The structure of coupling between the thermally deformable member 440 and the friction member 430 can be variously implemented.

[0047] The rod 420 and the shape memory alloy, that is, the thermally deformable member 440, are loose-fitted with a predetermined interval therebetween, and the friction member 430 and the thermally deformable member 440 are coupled to be tightly attached to each other. The shape memory alloy is deformed in a circumferential direction, and the interval between the shape memory alloy and the rod 420 is a space where the shape memory alloy contracts it is deformation.

[0048]FIGS. 6 and 7 are front sectional view and partially enlarged view of a damper having another thermally deformable member in accordance with the present invention, and FIG. 8 is a side sectional view of the damper.

[0049] As shown in these drawings, a thermally deformable member 440 is made of bi-metal. The bi-metal, the thermally deformable member 440, includes a first annular metal 442 having a predetermined thickness and length, and a second annular metal 443 having a predetermined thickness and length and coupled to an outer circumferential surface of the first annular metal 442. The first annular metal 442 and the second annular metal 443 are made from materials having different thermal expansion coefficients.

[0050] The first and second annular metals 442 and 443 can be cut out with a predetermined width at their sides.

[0051] The bi-metal, the thermally deformable member 440, is insertedly coupled into the coupling groove 423 of the rod, and the friction member 430 is coupled at an outer circumferential surface of the bi-metal. At this time, the friction member 430 is tightly attached to the friction surface (FS) of the receiving space 411 of the cylinder.

[0052] The bi-metal, that is, the thermally deformable member 440, and the rod 420 are loose-fitted with a predetermined interval therebetween, and the friction member 430 and the bi-metal 440 are coupled to be tightly attached to each other. The bi-metal is deformed in a circumferential direction, and the interval between the bi-metal and the rod 420 is a space where the bi-metal is moved in its deformation.

[0053] The heating unit 450 is a coil heater, and can be implemented by a different unit. The coil heater is insertedly coupled into the rod 420 and arranged inside the rod 420 corresponding to the area where the thermally deformable member 440.

[0054] A guide bush 460 is coupled to an inner circumferential surface of an entrance of the receiving space 411 of the cylinder. The guide bush 460 seals to a degree between the entrance of the receiving space 411 and the outer circumferential surface of the rod 420.

[0055] The thermally deformable member 440 can be implemented in various forms. If the thermally deformable member 440 is heated in a different form to a high temperature, it expands by itself to make the friction member 430 be tightly attached to the friction surface (FS) and generate a friction force therebetween. Meanwhile, if the thermally deformable member 440 is not heated and its temperature is low, the thermally deformable member 440 contracts, separating the friction member 430 from the friction surface (FS).

[0056] In a different embodiment of the damper of the present invention, the friction member 430, the thermally deformable member 440 and the heating unit 450 can be coupled at the side of the cylinder 410, while the friction surface (FS) can be provided at the outer circumferential surface of the rod 420.

[0057]FIG. 9 is a front sectional view showing a washing machine having the damper in accordance with the present invention. The same reference numerals are given to the same elements as those of the conventional art.

[0058] As shown, the washing machine includes a cabinet 100 having an internal space in a predetermined shape; a tub assembly 200 positioned inside the cabinet 100; a spring 110 for connecting an upper portion of the tub assembly 200 and the cabinet 100; a cylinder 410 having a receiving space 411 with a predetermined depth in a longitudinal direction at one side and being coupled to the tub assembly 200 at the other side; a rod 420 of which one side is inserted to be movable relatively in a longitudinal direction into the receiving space 411 of the cylinder and the other side is coupled to the cabinet 100; a friction surface (FS) formed at an inner circumferential surface of the receiving space 411 of the cylinder; a friction member 430 coupled to the side of the rod 420 so as to be rub-contacted with the friction surface (FS); a thermally deformable member 440 for tightly attaching the friction member 430 to the friction surface (FS) or separating it therefrom by being deformed according to a temperature change; and a heating unit 450 for thermally deforming the thermally deformable member 440.

[0059] The tub assembly 200 includes a tub 210 positioned inside the cabinet 100; a drum 220 rotatably inserted in the tub 210 and receiving the laundry; and a driving motor 230 mounted at a rear surface of the tub 210 and rotating the drum 220.

[0060] One side of the cylinder 410 can be coupled to the cabinet 100, and one side of the rod 420 can be coupled to the tub assembly 200.

[0061] In the cabinet 100, there are provided a water supply unit (not shown) for supplying washing water into the tub 210, a water discharge unit (not shown) for discharging washing water from the tub 210; and a door (not shown) for opening and closing the drum 220.

[0062] The cylinder 410, the rod 420, the thermally deformable member 440, the friction member 430 and the heating unit 450 constitute a damper 400. The damper 400 has the same structure as described above, descriptions of which are thus omitted.

[0063] The operational effect of the damper and the washing machine having the damper will now be described.

[0064] First, when a relatively small amount of vibration is transferred to the damper 400, power is supplied to the heating unit 450, heating the heating unit. Then, as the heat of the heating unit 450 is transferred to the thermally deformable member 440, an outer diameter of the thermally deformable member 440 is reduced, and accordingly, the friction member 430 is separated to a degree from the friction surface (FS), and in this state, the rod 420 makes a relative movement in the receiving space 411 of the cylinder 410, absorbing the small amount of vibration.

[0065] If a relatively large amount of vibration is transferred from an external source to the damper, power supply to the heating unit 450 is cut off, to prevent heat generation of the heating unit 450. Then, as shown in FIG. 11, the outer diameter of the thermally deformable member 440 is enlarged, so that the friction member 430 is tightly attached to the friction surface (FS), and in this state, the rod 420 makes a relatively movement in the receiving space 411 of the cylinder 410, absorbing the excessive vibration.

[0066] The above descriptions are for the operation of the damper of which the thermally deformable member 440 is the shape memory alloy, and if the thermally deformable member 440 of the damper is the bi-metal, the damper is operated in the similar manner.

[0067] Meanwhile, in a different embodiment of the thermally deformable member 440, in case that the thermally deformable member expands at a relatively high temperature and contracts at a relatively low temperature, if the heating unit 450 is heated, the friction member 430 is tightly attached to the friction surface (FS) to absorb the excessive vibration, whereas if the heating unit 450 is not heated, the friction member 430 is separated from the friction surface (FS) to absorb the small amount of vibration.

[0068] In that way, the damper absorbs both the excessive vibration and the relatively small vibration.

[0069] The operation of the washing machine subsequently proceeds with a washing process, a rinsing process and a dewatering process.

[0070] Among the processes, an excessive vibration is generated from the tub assembly 200 when it reaches a normal dewatering process, and the excessive vibration is transferred to the damper 400. At this time, since no power is supplied to the heating unit 450, the friction member 430 is tightly attached to the friction surface (FS), and in this state, the rod 420 makes a relative movement in the receiving space 411 to absorb the excessive vibration according to friction between the friction member 430 and the friction surface (FS), to thereby minimize transfer of the excessive vibration generated from the tub assembly 200 to the cabinet 100.

[0071] In the process that a relatively small amount of vibration is generated, that is, in the washing process or in the process in which dewatering is performed at a normal dewatering speed, a relatively small amount of vibration is generated from the tub assembly 200, which is then transferred to the damper 400. At this time, power is supplied to the heating unit 450, heating the heating unit. Then, as the outer diameter of the thermally deformable member contracts, the friction member 430 is separated to a degree from the friction surface (FS). In this state, the rod 420 makes a relative movement in the receiving space 411 of the cylinder 410, to absorb the small amount of vibration transferred from the tub assembly 200.

[0072] In this manner, in the washing machine, both small and excessive vibrations generated from the tub assembly 200 in the entire process of washing the laundry are absorbed, so that vibration noise generated from the cabinet 100 can be minimized.

[0073] As so far described, the damper and the washing machine having the damper of the present invention have the following advantages.

[0074] That is, for example, the damper absorbs all the large or small amounts of vibrations generated from other systems to prevent transfer of the vibration to other components, so that a stability and reliability of the system can be enhanced.

[0075] In addition, with the washing machine adopting the damper, the large or small amounts of vibrations generated from the tub assembly 200 in the entire process of washing the laundry are prevented from being transferred to the cabinet, so that a vibration noise generated outwardly can be minimized while the washing machine is in use. Therefore, a reliability of the product can be improved.

[0076] As the present invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be construed broadly within its spirit and scope as defined in the appended claims, and therefore all changes and modifications that fall within the metes and bounds of the claims, or equivalence of such metes and bounds are therefore intended to be embraced by the appended claims. 

What is claimed is:
 1. A damper comprising: a cylinder having a receiving space with a predetermined depth in a longitudinal direction on one side thereof; a rod inserted to be movable relatively in a longitudinal direction in the receiving space of the cylinder; a friction surface formed at one side of the cylinder and the rod; a friction member positioned at the cylinder or the rod and rubbing on the friction surface; a thermally deformable member being deformed according to a change in a temperature to make the friction member be tightly attached to the friction surface or separated therefrom; and a heating unit for thermally deforming the thermally deformable member.
 2. The damper of claim 1, wherein the receiving space of the cylinder has a cylindrical shape, and the friction surface (FS) is formed at an inner circumferential surface of the receiving space of the cylinder.
 3. The damper of claim 1, wherein the friction member has a ring shape with a predetermined thickness and length.
 4. The damper of claim 3, wherein the annular friction member has one side cut out with a predetermined width.
 5. The damper of claim 1, wherein if the thermally deformable member is heated at a high temperature, it contracts and separates the friction member from the friction surface, whereas if the thermally deformable member is not heated with no heat applied thereto, it expands to make the friction member be tightly attached to the friction surface and generate a friction force.
 6. The damper of claim 1, wherein if the thermally deformable member is heated at a high temperature, it expands to make the friction member be tightly attached to the friction surface and generate a friction force, whereas if the thermally deformable member is not heated with no heat applied thereto, it contracts and separates the friction member from the friction surface.
 7. The damper of claim 1, wherein the thermally deformable member is a shape memory alloy.
 8. The damper of claim 7, wherein the shape memory alloy has a ring shape with a predetermined thickness and length, of which one side is cut out with a predetermined width.
 9. The damper of claim 1, wherein the thermally deformable member is made of bi-metal.
 10. The damper of claim 9, wherein the bi-metal comprises: a first annular metal having a predetermined thickness and length; and a second annular metal having a predetermined thickness and length, coupled to an outer circumferential surface of the first annular metal, and being made of a material with a different thermal expansion coefficient from the first annular metal.
 11. The damper of claim 10, wherein the first and second annular metals have one side, respectively, cut out with a predetermined width.
 12. The damper of claim 1, wherein the heating unit is a coil heater.
 13. The damper of claim 1, wherein the thermally deformable member is coupled to an outer side of the rod positioned inside the receiving space of the cylinder, the heating unit is mounted inside the rod, and the friction member is coupled to an outer side of the thermally deformable member and faces the friction surface (FS).
 14. The damper of claim 13, wherein there is a predetermined interval between the thermally deformable member and the rod.
 15. The damper of claim 13, wherein a coupling groove is formed with a predetermined depth and length at an outer side of the rod, into which the thermally deformable member is inserted, and a coupling groove is formed with a predetermined depth and length at an outer side of the thermally deformable member, into which the friction member is inserted.
 16. A washing machine including a cabinet having an internal space in a predetermined shape and a tub positioned inside the cabinet and filled with washing water, comprising: a cylinder having a receiving space with a predetermined depth in a longitudinal direction at one side and being coupled to the cabinet or to the tub at the other side; a rod having one side inserted to be movable relatively in a longitudinal direction in the receiving space of the cylinder and the other side coupled to the cabinet or the tub; a friction surface formed at the cylinder or at the rod; a friction member positioned at the cylinder or at the rod so as to rub on the friction surface; a thermally deformed member for making the friction member be tightly attached to the friction surface or separated therefrom by being deformed according to a temperature change; and is a heating unit for thermally deforming the thermally deformable member. 